1. Field of the Invention
The present invention relates to a vehicle headlamp that includes in a lamp chamber thereof a plurality of tiltable lamp units.
2. Prior Art
In one known vehicle headlamp structure, a plurality of lamp units that are installed so as to tilt are housed in a lamp chamber thereof that is defined by a front cover and a lamp body.
For example, in Japanese Utility Model Application Publication No. S58-68602, a pair of right and left lamp units are housed side by side in a lamp chamber, and these two lamp units are tiltably provided in the lamp body by corresponding aiming mechanisms. In this vehicle headlamp, a plurality of (three) supporting portions for supporting a plurality of aiming members (that comprise an aiming fulcrum pin and two aiming screws) that constitute the aiming mechanism are provided in the back of each one of the two lamp units.
In this conventional vehicle headlamp, one lamp unit and its aiming mechanism form a unit. As a result, a plurality of supporting portions are provided with certain distances in between in the lateral direction for each lamp unit. Thus, the lamp structure needs a certain lateral length. However, this causes a problem. A compact lamp apparatus cannot be easily built.
Such a problem can be solved by installing a single aiming mechanism that can tilt a pair of lamp units as disclosed in, for instance, Japanese Patent Application Laid-Open (Kokai) No. H8-264005. This arrangement, however, causes a new problem. It is not possible to independently make an aiming adjustment of each lamp unit.
In view of the above, the object of the present invention is to provide a vehicle headlamp that includes a plurality of lamp units, wherein not only can the vehicle headlamp be made compact but also the aiming adjustment can be performed independently for each one of the lamp units.
The present invention accomplishes this object by way of devising a novel structure for an aiming mechanism for each lamp unit.
More specifically, the present invention is for a vehicle headlamp in which first and second lamp units are housed adjacent to each other in a lamp chamber that is defined by a front cover and a lamp body and provided in a tiltable fashion in the lamp body by first and second aiming mechanisms, respectively, and in the present invention:
a plurality of first supporting portions for supporting a plurality of aiming members that constitute the first aiming mechanism are provided in the rear portion of the first lamp unit in the lamp body, and a plurality of second supporting portions for supporting a plurality of aiming members that constitute the second aiming mechanism are provided in the rear portion of the second lamp unit in the lamp body; and
at least one of the plurality of the first supporting portions and at least one of the plurality of the second supporting portions are provided so as to overlap each other with reference to a direction of sidewise installation of the first and second lamp units.
In this structure, the first and second lamp units are housed in the lamp chamber adjacent to each other, and they are installed laterally, vertically or obliquely.
The vehicle headlamp contains two (the first and second) lamp units in the lamp chamber, and it may contain an additional third lamp unit. When the third lamp unit is installed and it has its own aiming mechanism, then a plurality of supporting portions for supporting a plurality of aiming members that constitute the aiming mechanism of the third lamp unit are provided between the first and second supporting portions of the first and second lamp units.
The structure of each one of the lamp units is not limited. For example, the lamp unit may be of a parabola type that has a reflector formed with reference to a rotary parabolic plane or the like. The lamp unit may also be of a projector type that is comprised of: a light source that is disposed in substantially coaxial with an optical axis that extends in a vehicle longitudinal direction, a reflector that reflects the light from the light source toward the front and toward the optical axis, and a condensing lens provided in front of the reflector.
The structure of the light source for each one of the lamp units is not limited, either. The light source can be a discharge light emitting portion of a discharge bulb, and it also can be a filament of an incandescent bulb such as a halogen bulb.
As seen from the above, in the vehicle headlamp structure according to the present invention, the first and second lamp units that are housed adjacent to each other in the lamp chamber are installed tiltably in the lamp body by the first and second aiming mechanisms, respectively. In addition, a plurality of first supporting portions for supporting the plurality of aiming members that constitute the first aiming mechanism are provided behind the first lamp unit in the lamp body, and a plurality of second supporting portions for supporting the plurality of aiming members that constitute the second aiming mechanism are provided behind the second lamp unit in the lamp body. In this structure, at least one of the plurality of the first supporting portions and at least one of the plurality of the second supporting portions are provided so as to overlap each other in the arranging direction of the two lamp units that are installed sideways when viewed the lamp body from the front. As a result, the present invention provides the operational advantages as described below.
Though in the prior art, a lamp unit and its aiming mechanism are designed as a single lamp structural unit, and a plurality of these lamp structural units are disposed parallel to each other; in the present invention, at least a part of one lamp unit and at least a part of another lamp unit are installed in an overlapped positional relationship in the direction of the height of the lamp body so that these lamp units are geometrically associated with each other. This reduces the width of the lamp body in the direction of installation of the lamp units.
According to the vehicle headlamp of the present invention that has in its lamp chamber a plurality of lamp units in a tiltable fashion, the headlamp can be made compact, and an aiming adjustment can be made independently for each one of the lamp units.
In the present invention, the second lamp unit can be installed somewhat behind the first lamp unit. Accordingly, for a lamp apparatus (headlamp) which has a front cover that curves to extend from the first lamp unit to the second lamp unit that is behind the first lamp unit, the lamp apparatus can be formed compact since the present invention effectively utilizes the inner space of the lamp chamber.
In the above structure, a front stage portion and a rear stage portion, which are offset from each other in the longitudinal (front and back) direction in the lamp chamber, is formed at a position at which at least one of the first supporting portions of the first lamp unit is provided behind at least one of the second supporting portions of the second lamp unit; and at least one of the first supporting portions is provided on the front stage portion, and at least one of the second supporting portions is provided on the rear stage portion. In this structure, such two lamp units and the aiming mechanisms therefor are disposed without any interfere with each other.
In addition, in the above structure, the second lamp unit disposed behind the first lamp unit can be a projector type lamp unit. The projector type lamp unit generally has a narrower opening than the lamp unit of a parabola type in regards to a reflector; as a result, each of the aiming members that constitute the aiming; mechanism of the projector type lamp is provided at a position away from the reflector when viewed from the front. Accordingly, when the projector type lamp unit is installed as the second lamp unit of the present invention, the light distribution performance of the second lamp unit will not be hindered, even if the reflector or other parts of the first lamp unit is disposed in front of each aiming member of the projector type second lamp unit. Thus, the width of the lamp apparatus (headlamp) can be effectively reduced.